Circuit arrangement for reducing the call losses in telephone systems with registers



May 13, 1958 v CIRCUIT ARRANGEM LOSSES IN WIT A. PFAU ENT FOR REDUCINGTHE CALL .TELEPHONE SYSTEMS H REGISTERS Filed Sept. 21, 1955 l NVENTORA. PFAU ATTORNEY United States Patent @fiice Patented May 13, .1 958CIRCUIT ARRANCEMENT FOR REDUCING THE CALL LOSSES IN TELEPHONE SYSTEMSWITH REGISTERS Anton Pfau, Stuttgart, Germany, assignor to InternationalStandard Electric Corporation, New York, N. Y., a corporation ofDelaware Application September. 21, 1953, Serial No. 381,382

Claims priority, application Germany September 20, 1952 9 Claims. (Cl.179-46) The present invention relates to telephone systems usingregisters, in which selectors, as well as all-relay arrangements, areused as connecting devices. Selectors or switches, as is Well known, areemployed as connecting links between registers and speaking wires. Thesetting time, which is 'required for the connection, causes call lossesifthe time between the sewing impulse and the first dial impulse isshorter than the setting time. One

specially provided control wires, whereas the residual dial impulses aretransmitted via a normal control wire and without an intermediatestoring to the common controlling device.

For the switching-on of a free register via a switching device to acontrolling device, consisting in the present case of a discriminatingselector or so-called finder, there are four possibilities with regardto the time, namely:

(1 The register may be connected prior to thean'ival of the first dialimpulse. I

(2) The register is switched-on by the finder between the first and thesecond dial impulse.

(3) T he register is switched-on by the finder at the arrival of thesecond dial impulse.

(4) No register is available at the arrival of the second dial impulse.

By means of the intermediate storing of the first dial impulses of atrain otimpulses, an additional time will still be available for theswi-tch-ingon of a free register, so that in this case a delayedswitching-on can be awaited, thereby diminishing the possibilities ofcall losses. Generally it may besutficient to store merely the firstdial impulse of the first train of impulses in the collecting device andtotransmit'this first impulse to the register simultaneously with thesecond dial-impulse, the register having been switched on in theameantime. By this measure the switching-on time will be extended by oneimpulse, i. e. by -ililfiimilliseconds." By .the intermediate storing ofthe first dial impulse it is possible furthermoreto-omitthe-seizing-signal, to carry'out-theseizing ofathe connectingdevice, and to comply with the demand ofsthe registers connectedtherewith, by-the first dial impulse itself.

The particulars of the present invention will be described withreference toanexample of an embodiment, without the inventionbeing-limited to the scope of. the

shown example. The accompanying circuit diagram shows a discriminatingselector RW, a finder MS and a register Reg. In all parts ofthe circuitdiagram only those circuits are shown'which-are necessary forunderstanding the invention. The finder MS, serving the switching-on ofthe register to the discriminating selector, is represented as a rotaryselector for reasons of simplicity, although for this purpose alsorelay-like switches maybe used. The employment of relay-like switcheshas the further advantage according to which no additional relays arenecessary for the operation of the discriminating selector, since themagnets available in the switch take over the switching operationswhichare required for the intermediate registering.

Where relays have more than one winding, each winding is illustrated byits individual rectangle provided with a Roman numeral designating thenumber of the winding, the number I usually being used to designate theoperating winding andother numbers being used to designate holdwindings. Thus, E l represents the operating winding of relay E and E 11represents the hold winding.

It is assumed that the seizing impulse is applied to the c-wire by atransmitting device which is not shown. By this means the seizing relayC will be energized in the discriminating selector RW and will lock overcontact c The test circuit for the switching-on of the register will beprepared by contact c and the circuit -An for starting the register willbe completed by contact-e Also, a circuit for relay E will be preparedat contact c The finder MS will then start to hunt for the callingdiscriminating selector and when its terminal is reached the testcircuit is completed for relays B in the register and R is thediscriminating selector from ground in the register, via relay B in theregister, wiper III of the finder MS, relay R in the discriminatingselector, contact e contact c resistance Wil, to negative battery. Thisseizes the register by opening the starting circuit at r The firstpositive dial impulse ofthe first train of impulses will be conducted tothe relay E via the lead WI and contact e whether or not the registerhas been seized. Relay E is thus operated and opens the circuit forrelay E to prevent its operating at this time. Relay E will be energizedby contact 2 This relay immediately holds itself via the contact e ofits own. Relay E also prepares the circuit for relay E The first dialimpulse is now registered in the relay E until the switching-on of theregister has been performed by the wiper II of the finder.

The transmission of the registered dial impulse to the register will beeffected after the connecting through to the register via relay E (II)and contact 2 wiper II of the finder MS via contact h to the relay X(I). In the meantime, at the termination of the first dial impulse, therelay E is de-energized, so that the relay E is now energized, via theprepared contact e and the dropped contact 2 The stepping circuit WIover which the dial impulses are transmitted, will be switched over bycontact e and the following dial impulses are then transmitted withoutan intermediate storing, via the wiper I of the finder MS to theregister Reg. because the contact r had likewise been reversed at theseizure by the operation of relay R.

It may happen that the first registered dial impulse and the seconddirectlytransmitted dial impulse, both of the first train of impulses,are conducted to the register simultaneously but over difiFerent wipersof they finder.

The delivery of the registered dial impulse is performed,

as described above, via the Wiper II of the finder MS, whereas allfollowing dial impulses of this train of impulses are conducted to theregister via the wiper I of the finder MS.

The dial impulses are received in the register with the aid of a chainof counting relays, consisting of the relays X X The first impulse,applied via the Wiper II of finder MS is received by the winding I ofthe counting relay X which operates. Relay V will be operated throughthe contacts x and k Then relay X will be locked in the counting chain,via winding X contacts x x v winding ofrelay H, r and b (relay B is theseizing relay of the register). Relay I-I operates in this circuit andby means of contact h shorts winding I of relay V, making it slow torelease. By means of the contact 11 the chain will be reversed for thereception of the following .impulses. By contact I1 the winding of relayX} will be disconnected and the registering of the first impulse in RWis cancelled. Relay E in the discriminating selector RW drops.

If the second impulse arrives through wiper I of MS, relay X is operatedvia the contacts Ir x relay X winding I, contact x and relay X windingII. Relay X closes a circuit at r to hold relay V. Relay X makes its ownholding circuit through winding II during the impulse. At the end of thesecond impulse, relay X releases. Relay X makes a holding circuit viaits own winding II and the contacts x to x h, relay H and the contacts rand b In this-holding circuit relay H remains operated also.

When the third impulse arrives via contacts h", x x relay X Winding I,contact x and relay X winding II, relay X operates. Relay X remainsoperated in this circuit during the impulse. Relay X holds itself viaits winding II etc. Additional'impulses operate the X relayssuccessively.

When the first impulse registered in the discriminating selector RWarrives at the register via wiper II of MS and the second impulsesimultaneously arrives directly via wiper I of MS, the counting relay X;will be energized directly via wiper II of MS, contact h and relay Xwinding I. At the same time the counting relay X .will be operated viawiper I, contacts h and I1 and relay X winding II. The relays V and Hwill be operated as already described. When the relays X and H areenergized, relays X holds itself via contacts h", x relay X winding I,contact x relay X winding II during the second impulse. Then relay Xreleases. of the chain continue as described.

Relay V remains operated during the impulse train. By each impulse ofthe train relay V gets a supply impulse. When the impulse train isfinished relay V releases after a delay by the release of the highestodd numbered X relay. In the counting chain the corresponding relay Xoperates the associated relay Z from ground via h h, 1 contact IV ofoperated X relay, winding of corresponding Z relay b Wi to negativebattery. By this means the recorded digit will be transmitted from thecounting chain to the Z-relays. Relay R1 operates via contacts h and zThe latter returns the counting chain of the X relays to the normalcondition by the release of any X relays which are then held. Therelease of relay H is also effected, so that the chain can receive thenext impulse train.

Relay H operates via the contacts 1' and k and locks via the contacts hand N, and this relay changes over the counting chain at h By this meansthe first impulse arriving via wiper I will not be conducted to relay Xwinding II, but to relay X winding II. The operation of relay H releasesrelay R at h For the second impulse train the first impulse will not beregistered in the discriminating selector RW, because E is operated, butwill be immediately transmitted via wiper I of finder MS into theregister through the contacts h and I1 Relay X operates. During thefirst impulse, a positive The functions impulse potential is appliedfrom the dial impulse input WI to relay X winding II via the contacts 11and hf. Relay X operates and immediately afterwards relay V operatestoo. Relay H cannot operate at this time via the contacts x to x becauseit is thus short circuited. As soon as the first impulse is finished,relay H operates in the circuit already mentioned and changes over thecounting chain for the reception of following impulse trains. v

In the present embodiment the register is provided for the reception oftwo impulse trains. It is obvious that the register can be arranged toreceive more impulse trains. The reception of the following impulsetrain is carried out in the same manner as described for the secondimpulse train.

In case the second dial impulse arrives prior to the switching-on of theregister in which case the relay R will not have been energized, thenthe second dial impulse will be transmitted via the impulse lead WI andthe contacts e r to relay E Relay B; will operate and by contacts a} andthe starting lead and the test lead, respectively, leading to theregister will be interrupted. By means of contact a ground will beapplied to the busy tone circuit Bez. and a busy tone signal will begiven to the calling subscriber.

What is claimed is:

l. A circuit arrangement for telecommunication systems comprising aplurality of selectors arranged in groups a register for each group,means responsive to an impulse from one of said selectors for seizingthe register associated therewith and for connecting said registerthereto over a plurality of connecting paths, means at each of saidselectors for receiving dial impulses, means at each of said selectorsfor storing a particular number of the first train of dial impulses tobe received, means operative subsequent to the connection of a registerfor transmitting said particular number of stored dial impulses to saidconnected register over a first path in said connecting means, and meansfor transmitting succeeding dial impulses over a second path in saidconnecting means.

2. A circuit arrangement, as defined in claim 1,,further comprisingmeans at each selector for rendering the impulse storing meansinoperative after the first train of dial impulses has been received andfor transmitting the second train of dial impulses directly to theconnected register as said second train of impulses is received by saidselector.

3. A circuit arrangement, as defined in claim 2 further comprising achain of relays in the register, means at the register for causing thefirst impulse of the first train of impulses to be received over thesecond path of the connecting means to operate the second relay of thechain of relays, and means at the register responsive to the end of thefirst train of impulses for causing the first impulse of the secondtrain to be received over said second path to operate the first relay ofsaid chain.

4. A circuit arrangement, as defined in claim 3, further comprisingmeans in each selector for preventing the operation of the connectingmeans if said connecting means has not operated prior to the receipt ofthe dial impulse following the particular number of impulses to bestored.

5. A circuit arrangement, as defined in claim 4, further comprisingmeans operated by the means for preventing the operation of theconnecting means for transmitting a signal to a busy tone circuit.

6. A circuit arrangement, as defined in claim 5, further comprisingcircuit means at the register for receiving the stored impulses at anytime after the initiation of the first dial impulse up to and includingthe initiation of the transmission of the impulse next succeeding theparticular number of stored impulses.

7. A circuit arrangement, as defined in claim 1, further comprisingcircuit means at the register for receiv ing the stored impulses at anytime after the initiation of the first dial impulse up to and includingthe initiation ther' comprising means operated by the means for preofthe transmission of the impulses next succeeding the venting theoperation of the connecting means for transparticular number of storedimpulses. mitting a signal to a busy tone circuit.

8. A circuit arrangement, as defined in claim 1, further comprisingmeans in each selector for preventing 5 ReferencesCited in the file ofthis patent the operation of the connecting means if said connectingmeans has not operated prior to the receipt of the dial im- UNITEDSTATES PATENTS pulse following the particular number of impulses to be2,300,329 G d h N v, 3, 1942 2,562,717 Holden July 31, 1951 9. A circuitarrangement, as defined in claim 8, furl0

